When a power supply management module in existing terminal devices (e.g., cell phone, tablet computer) supplies power to external element (e.g., smart card, SD card), a power supplying strategy is adopted for the purpose of saving the power, in which power is on during use and power is off automatically when the external element is not in-use for a long time. However, this auto power-off strategy has a hidden danger in case two systems co-exist. For example, when an application of one operating system is using an external element, since this operating system is temporarily switched to another operating system so that power is off, an unexpected abnormality of the external element will be caused. Especially, a switch between a secure operating system running in a trusted execution environment and a multimedia operating system running in an untrusted execution environment will make secure element previously associated with the secure operating system power-off.
Therefore, there is a need for a method and terminal device for continuously supplying power to external element.